The invention generally relates to a projection system.
An ever-increasing number of applications are using display devices that are derived from a combination of liquid crystal optics technology and semiconductor technology. For example, these display devices may be used in mobile telephones, projection systems, home entertainment systems and monitors for personal computers.
Examples of these display devices may include field emission displays (FEDs) and spatial light modulators (SLMs). For example, the SLMs may be used in a projection system to form a modulated beam image, and for color projection systems, the system may have one SLM for each primary color channel (red, green and blue (RGB) primary color channels, as examples) of the projection system. As an example, to form a projected multicolor image, one SLM may modulate a red beam (of the red channel) to form a red modulated beam image, one SLM may modulate a green beam (of the green channel) to form a green modulated beam image, and another SLM may modulate a blue beam (of the blue channel) to form a blue modulated beam image. In this manner, the red, green and blue modulated beam images combine on a projection screen to form the multicolor image.
A conventional color projection system 10 is illustrated in FIG. 1. The projection system 10 may include a light source 28 that generates a beam of white light. For purposes of separating the beam of white light into its primary red, green and blue beams (of the different color channels), the projection system 10 may include dichroic beam splitters 12 and 16. In this manner, the dichroic beam splitter 12 may separate a red beam, for example, from the white beam of light, and a mirror 13 may reflect the red beam to a polarizing beam splitter 19 that, in turn, reflects the red beam to a reflective SLM 14 that modulates the red beam. The polarizing beam splitter 19 directs the resultant green modulated beam of light to an X-cube prism 24 that directs the modulated beam through projection optics 26 to form one component of the multicolor image, the green modulated beam image, on a display screen (not shown). The projection system 10 typically includes additional optical devices, such as the dichroic beam splitter 16, and polarizing beam splitters 17 and 22 to direct the unmodulated green and blue beams (from the original white beam) to an SLM 18 and an SLM 20, respectively. The polarizing beam splitters 17 and 22 and the X-cube prism 24 direct the resultant green and blue modulated images through the projection optics 26 to form the remaining components of the multicolor image.
In the projection system 10, optical communication with a viewer of the system 10 occurs in one general direction, i.e., in the general direction from the SLMs 14, 18 and 20 to the display screen. However, the projection system 10 may need input from the viewer. For example, the projection system may be part of a computer system that is used to establish an interactive gaming environment. In this manner, the viewer of the display may provide input through a remote control device, for example, to change the image or as another example, to alter sound that is associated with the image. Unfortunately, the computer system may need an additional device, such as an infrared receiver, to receive and decode an infrared light wave from the remote control device.
Thus, there is a continuing need for a system that addresses one or more of the problems stated above.